Kubyshka is an early East Slavic ceramic jar or pot with narrow hole, short or absent neck and wide, rounded body.КУБЫ́ШКА, in: Словарь русского языка в 4-х томах (:ru:Малый академический словарь) (A Dictionary of Russian Language), Moscow, Русский язык, 1999. In the past the term kubyshka, a diminutive derivation from the word Куб (kub) in the generic meaning of "container",Article "Куб" in: Max Vasmer, Etymological dictionary of the Russian language had a broader meaning of various rounded containers, e.g. a barrel or birch bark kubyshka.Vladimir Dahl, Толковый словарь живого великорусского языка
The word has become associated with buried hoardsA footnote in: The Nuclear Deception: Nikita Khrushchev and the Cuban Missile Crisis, p. 136 and is used in a number of idioms associated with hoarding or reserve saving (держать в кубышке (keep in a kubyshka), класть в кубышку (put into a kubyshka), etc.).
The word is also used as a euphemism or a nickname for a short, plump person.James B. Woodward, Gogol's "Dead Souls" p. 179 For example, in Sergei Prokofiev's ballet Cinderella, a wicked stepsister's nickname Kubyshka was variously translated as Fatty,Sergei Prokofiev: A Biography, p. 419 Dumpy, etc. Grand Duchess Anastasia, the daughter of tsar Nicholas II of Russia was nicknamed "Kubyshka".Helen Rappaport, The Last Days of the Romanovs: Tragedy at Ekaterinburg, p. 82
References